1. Technical Field
The instant disclosure relates to an optical navigation device; in particular, to an optical navigation device without any optical lens for focusing a reflected light.
2. Description of Related Art
Currently, the “holeless” design has been applied to lots of optical navigation devices to provide a great protection against dust. Generally speaking, these optical navigation devices have optical lenses to prevent the reflected light which the light is generated by the light source and reflected from the cover from entering the sensing array, wherein the reflected light from the cover entering the sensing array causes interferences that decrease the sensing accuracy. However, if the distance between the light source and the image sensor decreases, it will be hard to prevent the reflected light from the cover from entering the sensing array just by disposing the optical lens. Therefore, for the “holeless” optical navigation device without any optical lens, one other specific design should be required to prevent the reflected light which the light is generated by the light source and reflected from the cover from entering the sensing array.